Picture changes during blinks: Looking without seeing and seeing without looking

Observers inspected normal, high quality colour displays of everyday visual scenes while their eye movements were recorded. A large display change occurred each time an eye blink occurred. Display changes could either involve Central Interest or Marginal Interest locations, as determined from descriptions obtained from independent judges in a prior pilot experiment. Visual salience, as determined by luminance, colour, and position of the Central and Marginal Interest changes were equalized. The results obtained were very similar to those obtained in prior experiments showing failure to detect changes occurring simultaneously with saccades, flicker, or mudsplashes in the visual scene: Many changes were very hard to detect, and Marginal Interest changes were harder to detect than Central Interest changes. Analysis of eye movements showed, as expected, that the probability of detecting a change depended on the eye's distance from the change location. However a surprising finding was that both for Central and Marginal Interest changes, even when observers were directly fixating the change locations (within 1 degree), more than 40% of the time they still failed to see the changes. It seems that looking at something does not guarantee you see it. The results are interpreted in terms of the idea that what the observer sees during scene exploration is not determined primarily by the location in the scene being fixated by the eyes, but by the scene aspects being attended to. A theory is summarized which applies to the other experiments in the literature on change blindness, and some new predictions are put forward.